Bonding Wire Joint Structure for Thermal Expansion Mismatch
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Solution Overview
Problem
Semiconductor devices experience distortion and cracking at joint parts due to thermal expansion coefficient differences between bonding wires and semiconductor chips, leading to reduced service life, especially under increasing high-temperature operating conditions.
Innovation Solution
A semiconductor device design that incorporates a connecting substrate with a thermal expansion coefficient matching or closely matching the bonding wire, reducing thermal expansion differences and minimizing distortion, thereby preventing cracks and extending service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a buffer plate with intermediate linear expansion coefficient is provided between Al wire and power semiconductor element, then stress applied to the joint part is decreased, but distortion at the joint part and crack occurrence cannot be sufficiently reduced
Solution Approach 1:
The invention changes the thermal expansion coefficient parameter of the connecting substrate to match or be less than that of the bonding wire, with a difference of 5 ppm/K or less. This parameter optimization directly reduces thermal stress and distortion at the joint part, preventing crack formation and extending service life under high-temperature conditions.
Solution Approach 2:
The connecting substrate serves as an intermediary component between the bonding wire and the electrode. By selecting a material with a thermal expansion coefficient matched to the bonding wire rather than the electrode, it acts as a thermal expansion mediator that protects the bonding wire joint from excessive stress while still providing electrical connection functionality.
2Ease of manufacture
If the thermal expansion coefficient difference between bonding wire and jointed member is large, then ease of manufacture is improved, but distortion at joint part increases and cracks occur
Solution Approach 1:
The invention optimizes the thermal expansion coefficient parameter of the connecting substrate material to be within 5 ppm/K difference from the bonding wire. This precise parameter control reduces joint part distortion during manufacturing and assembly processes, enabling better manufacturing precision without significantly complicating the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces distortion and crack occurrence at joint parts, enhancing the service life of semiconductor devices by matching the thermal expansion coefficient of the connecting substrate with the bonding wire, thus improving reliability under high-temperature conditions.
Implementation Method 1
a thermal expansion coefficient of the connecting substrate is equal to a thermal expansion coefficient of the bonding wire, or the thermal expansion coefficient of the connecting substrate is within a range of the thermal expansion coefficient of the bonding wire or less
Data Source
AI summary
A semiconductor device includes: a semiconductor chip; a bonding wire electrically connected to an electrode provided on the semiconductor chip; and a connecting substrate jointed to the electrode of the semiconductor chip, in which: a thermal expansion coefficient of the connecting substrate is equal to a thermal expansion coefficient of the bonding wire, or the thermal expansion coefficient of the connecting substrate is within a range of the thermal expansion coefficient of the bonding wire or less and a first thermal expansion coefficient or greater, a difference between the first thermal expansion coefficient and the thermal expansion coefficient of the bonding wire is a predetermined value, and the bonding wire is jointed to the connecting substrate to be electrically connected to the electrode via the connecting substrate.